This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. HIV vaccine development has been complicated by the extensive antigenic variation displayed by HIV. As an alternative to targeting the virus, we have developed vaccines targeting CCR5, a selfprotein that is critically involved in HIV replication, transmission, and pathogenesis. By displaying peptides derived from CCR5 at high density on the surface of virus-like particles (VLPs), we have shown that we can efficiently overcome the mechanisms of B cell tolerance that normally limit the ability to induce high-titer IgG antibodies against self-proteins. Our VLP-based vaccines induce hightiter IgG antibodies against CCR5, these antibodies bind to native CCR5 and inhibit viral replication. In this project, we will evaluate the ability of a VLP-based vaccine targeting CCR5 to inhibit mucosal SIV infection of macaques. In Aim 1 we will evaluate the immunogenicity of our vaccines upon intramuscular and intravaginal inoculation. In Aim 2 we will challenge rhesus macaques via a vaginal challenge protocol and assess the protection provided by vaccination. These studies will allow us to assess the potential of vaccines targeting CCR5 to protect against HIV infection.